Both sides need a victory in Tokyo to stand any realistic chance of winning the four-team tournament with China expected to overpower Hong Kong in their final game.
Japan's meeting with title holders South Korea is being billed as a "game of guillotine" by media in both countries after some insipid displays from the World Cup-bound neighbours.
Hosts Japan were booed off the pitch after drawing 0-0 against China in their opening game while coach Takeshi Okada was still jeered despite a 3-0 win over Hong Kong in midweek.
The Koreans suffered their first defeat by China since the countries began playing full internationals in 1978 on Wednesday in a shock 3-0 reverse.
South Korea coach Huh Jung-moo was left clutching at straws as he blamed everything from the new players he had picked to the referee and probability theories.
"The odds were that our run against China would come to an end sometime," said Huh, whose team had torn apart Hong Kong 5-0 in their opener. "I have no fears about the Japan game."
Huh has made no bold claims about how far his South Korea team can go at the World Cup in South Africa - unlike Okada, who chose to declare Japan were targeting the semi-finals.
CHINA STALEMATE
Okada's refusal to back-track quickly came back to haunt him with a dour 0-0 draw in a home friendly with Venezuela before his side's stalemate with a vastly improved China.
"The World Cup is our main priority so it's important to win this title," Okada told reporters. "I accept the criticism but we are grinding out the results and making progress."
Remarks Okada made recently insisting South Korea's run to the 2002 World Cup semi-finals proved it was possible for Japan to match the feat ignored several crucial factors.
Korea's class of 2002 were arguably the best Asian side ever assembled, coached by a master tactician in Dutchman Guus Hiddink and backed by fervent home support.
"We have big goals," said a defiant Okada, although plummeting ticket sales pointed to frustration among Japan fans. "We will keep focusing on what we have to do to achieve them."
Thursday's crowd of 16,000 for the Hong Kong game was a record low for a Japan game at Tokyo's National Stadium since the J-League was launched in 1993.
Japan have never won the East Asian championship and will likely need to beat South Korea by more than the odd goal to win the title on goal difference, barring a slip-up by China.
"We fight on," said Okada. "I have no negative thoughts."
